All know ion generators have at least one screen positioned in front of the air ionizing electrodes. Normally it is a conducting screen, however at times device body elements, which are not necessarily conducting, might be used as a screen.
The screen acts as a passive electrode and it is needed for corona discharge generation between electrodes during which ions are generated.
The screen may have a certain potential or alternatively be grounded.
The Invention disclosed in U.S. Pat. No. 6,373,680 (Riskin) titled METHOD AND DEVICE FOR ION GENERATION exemplifies a device designated only for unipolar ionization, which in fact is one of its main disadvantages.
U.S. Pat. No. 4,740,862 shows in FIG. 1 an ion generator, in which the potential of the screen is close to zero. Ion generators are also known which are provided with two conducting screens mounted one after the other in front of the ionizing electrode (See U.S. Pat. No. 4,757,422 and U.S. Pat. No. 5,153,811).
The first screen in U.S. Pat. No. 4,757,422 has a zero potential and it serves to provide a corona discharge between this screen and the ionizing electrode.
The potential of the second screen in that invention is close to zero and serves as an imbalance sensor.
The first conducting screen in the device depicted in U.S. Pat. No. 5,153,811 FIG. 4 has a certain potential during operation.
The second screen in that invention is grounded.
The principal disadvantage of these and similar ion generators is their short operation life caused by dust precipitation on the ionizing electrodes, which results in gradual decrease of ions emission until its complete cessation.
This is because the electric field capable of accelerating ions is concentrated only between the ionizing electrode and the screen the potential of which is close to zero.
Since there are no construction elements generating electric fields external relatively to the apparatus beyond the screen, that are capable of carrying the ions away from the device, the ions are exported to the environment by an airflow directed through the corona discharge area, namely the area between the ionizing electrodes and the screen.
In virtue of the fact that the corona discharge area is actually an electrostatic filter, dust contained in the airflow precipitates on all the elements forming the corona system, including the ionizing electrode.
Besides, the known inventions do not provide any indication of the reduction or ceasing of ion emission.
One of the objects of the present invention is to generate stationary external electric field assisting to carry the ions away from the generator without allowing airflow to pass through the corona discharge area.
In order to attain the object of the invention, a first ion current is made to flow through the screen holding the electrode, generating positive ions, passes through a voltage stabilizer having a high positive potential in reference to the ground, and a second ion current is made to flow through the screen holding the electrode generating negative ions passes through a voltage stabilizer having high negative potential in reference to the ground, whereas for balancing the output of both ion currents, after passing the screens and voltage stabilizers, the ion currents are passed through capacitive network common for these currents.
Another object of the above invention is to provide self-balance of the positive and the negative output ion currents.
In methods and generators with balanced currents emitted by the ionizing electrode, the above object is attained by merely balancing the ion currents flowing via the screens to the ground.
In the method of the present invention the ion currents flowing via the screen to the ground are controlled by changing the screen potentials relative to the ground.
To do so, the ion currents emitted by each of the screens towards the ground, from separated circuits constituting voltage stabilizers, are passed through a capacitive network common for these currents.
In this case when the screen currents are equal, the voltage drop on the common capacitive network is equal to zero and the screen potentials are determined by their respective voltage stabilizers.
In case of screen currents imbalance, which might stem from an initial difference in the distances from the ends of the ionizing ion electrodes to the screens, bias voltage is generated on the common capacitive network, which acts as negative feedback and redistributes the screen potentials relative to the ground, which results in screen ion current balance, and consequently in self-balance of positive and negative output of ion currents.
At the same time the voltage difference between the screens remains unchanged and equal to the sum of voltage stabilizer voltages, which provides for steady value of the external electric field between the screens.
Even though in this invention the airflow passes beyond the generator borders rather than the corona discharge area, which in itself considerably reduces the electrodes contamination with dust and considerably increases the service life, another object of the invention is to support a constant ions emission level during the operation of the generator.
To attain this object, at least one of the ion currents emitted by the screens, or at least one of the ion currents emitted by the air ionizing electrodes are used as a feedback signal controlling the generator parameters.
In addition to the mentioned objects, one more object of this method is providing an indication of the need to clean the air ionizing electrodes from dust.
In order to attain this object, minimal value of the feedback signal below which the preset level of ion emission is not maintained, is used as an Indicating signal.
The proposed method of the present invention is implemented in ion generator, which has at least two air-ionizing electrodes, insulators with these electrodes mounted in them, conducting screens with electrodes arranged inside them, rectifying high voltage diodes, condenser, balancing ion currents emitted by the electrodes, stabilizers of the positive and negative screen voltage, condenser balancing the ion currents emitted by the screens, generator of high ac voltage, feedback network, comparator and indicator.